Leaf type filter



June 5, 1951 G. v. wooDY ET AL LEAF TYPE FILTER Filed May 22, 1948atented June 5, 1951 LEAF TYPE FILTER Guy V. Woody, Milwaukee, andCharles W. Bilbe, Wauwatosa, 'Wis., assignors toAllis-ChalmersManufacturing Company, Milwaukee, Wis., a

corporation o f Delaware Application May 22, 1948, Serial N o. 28,633

1 Claim.

VThis invention relates to improvements in filters of the multiple leaftype.

Filters are known to the prior art in which `a number of hollow leaflike elements covered `With fabric bags or other ltering media areinimersed in a tank supplied with the `fluid to be iiltered, thefiltrate Abeing removed from the interiors of the leaves, the solidsremaining on the external surface of the leaf and ultimately beingremoved from the 4leaves and from the bottom of the tank. One of theprincipal 'troubles with known filter constructions of the leaf type isthe lar-ge number of joints which must be sealed to prevent leakage ofthe filtrate.

The present invention concerns novel struc.- ture `for a filter unithaving a minimum .of external sealed joints. I An object of theinvention concerns provision for easy inspection and replacement offilter elements with a minimum disturbance .of sealed e external joints.i

Another object concerns novel structural arrangements to provide fordropping and removal "of lter cakes and brushing of bags and at the sametime for good filtrate drainage.

i More specifically, the invention is in the nature of an ingeniousstruct-ure providing for removal of `an .entire Amultiple filter ,leafassembly from the lter tank without disturbing incre than a minimumnumber of `sealed joints and in which there are no exposed jointsbetween the filter leaves and filtrate manifold when .the lter isassembled for ope-ration.

The invention having the above and still more objects and advantageswhich may appear hereinbelow may best be Acarried into practical effectas described hereinbelow with reference to the drawing in which likereference characters 4in- `Qdicate the same or similar parts throughoutthe several views.

Fig. 1 is a plan View of the filter of this invention with portions4broken away and partially in cross-section to show internal structure;

Fig. 2 is a front elevation of the lter of Fig. l with portions brokenaway and partially in crosssection to show internal structure;

Fig. 3 is a side view of a iilter leaf as shown in Fig. 2 to an enlargedscale with the bag and screen backing partly broken away to showinternal structure;

Fig. 4 is an edgewise view of the leaf Fig. 3; and

Fig. 5 is a cross-section of the leaf taken on line V-V of Fig. 3, to astill further enlarged scale.

The invention has been embodied in a pre- ZIO-181) ferred form ofapparatus illustrated in the drawing and in which I is a filter tank orhousing supported on suitable supports 2. Tank I has the form of a boxlike housing with a trough like lower portion 3 `for receiving settledsolids which will be removed during cleaning of a built in screwconve-yer 4, discharging through a cleanout door 6 of conventionalconstruction, which is sealed during filtration. A second cleanou-t door'I is provided in one lateral wall of the tank opposite to a largerectangular opening 8 in the opposite wall.

Tank 1 is reinforced by a heavy ange 8 abou the periphery of opening 8providing a seat for forming a sealed joint with one face of a headerplate -9 which -forms the backbone of the filter element assembly. rIhejoint will be secured as by bolts I I. The mixture of flu-id and -nesolids Vto be filtered is supplied to tank I through a -valved supplyconnection I2, and air may be vented or pressure relieved by a ventconnection I3 at the top.

The filter unit proper has, as its backbone, the header plate 9 whichhas `a plurality of parallel slots 9 piercing the plate within an areavsurrounded by an imperforate peripheral border portion which will beseated in sealed relation to the flange 8' oftank .I as shown in thedraw,- ing. A plurality of filter leaves IA are secured in edgewiserelation to the inner tank side lof the header plate 9, preferably in.parallel relation to :a .common reference plane which will be avertical plane normal to the plane of flange 8 when the header plate andfilter leaf assembly are vsecured in .place Yfor operation.

lt will be seen from Figs. 3 5 that eacl'rfilter leaf I 4 is composedIof a iianged edge member 1.6 having a tenon portion Il formed to tsnugly in one of the slots 9 of the header plate 9, the ange I8 havingprovisions `such as Aholes i9 for accommodation of bolts for securing it.to the :header plate. Suitable bolts are clearly indicated in Fig. 2 ofthe drawing at 2l. Sealing material (not shown) may be interposedbetween the ange I8 and the face of the header plate surrounding slot 9.One or more apertures 22 extend through member I6 normally to the planeof flange I8. The member i6 has a rather deep, narrow groove 23 adjacentthe flange I8. A framework 24 is attached to member I6 adjacent its endsand this framework is covered on both sides with a coarse mesh wirescreen 26 or other suitable grating to enclose a hollow interior spacewhich is open outwardly through apertures 22 of element I6. A filter bag2l suitably formed of close woven fabric or other suitable integument isfltted over the framework 24; and its edges are forced into lgroove 23and secured therein by forced filling the groove 23 with hammered-inlead wire 28 or other suitable caulking material. It Will be noted thatthe lowest of the apertures 22 permits communication betweensubstantially the lowest part of the interiol` of the filter leaf i4 andslot 9 of the header plate when the leaf is assembled for use with tankI.

It is self-evident that when a plurality of lter leaves is assembled asshown on header plate 9, and the header is secured in Yposition againstflange 8', that the joints between elements I4 and 4 by the screwconveyer. When desirable, door I can be opened and a suitable brush usedbetween the leaves to dislodge solids which will fall Y inserted in thetank, the joint at 8-9 being the only sealed joint to make.

It will be understood that the specific embodiment described andillustrated herein is illustrative only, and that the invention includessuch modifications and equivalents as may readily ocheader plate 9 willbe interior and that any leake age from tank I through these jointscould only ing the area occupied by slots 9. This manifold Y takes theform of a box like vstructure as shown and is provided with a ltrateoutlet 3i and an auxiliary connection 32 which can be used for a backpressureinlet for supply of compressed air or other gas tothe interiorof the leaves for the purpose of reversing the fluid pressure on the bagand dropping the filter cakes.

The dimensions of the lter leaves I4 are such that the assembly ofleaves will pass through the opening 8 so 'that the header and leafassembly may be attached to and removed from the tank I as a unit. Y

In operation fluid mixture to be filtered is supplied at connection I2,filling the tank, from which air may be vented at I3. The fluid can passthrough the integuments,V or bags 2l, to the interior of the leaves andthrough apertures 22 and the slots 9 to the interior of manifold 29 onthe other side of header plate 9, whence it .can pass via filtrateoutlet 3| to a point of use or storage. lThere is a minimum of sealedexternal .joints in the system, namely, the cleanout doors, one headerto tank joint, a stuffingV box for the screw conveyer drive shaft, andnecessary supply, vent and discharge connections. In use, "any smallleaks at the many joints Where the leaves I4 are secured to the header 9will be unimportant, as" the fluid will pass only to the interiorof-discharg'emanifold 29 where it belongs, and such smallVv leaks asmight occur will be clogged with solids; after a short period ofoperation so that only ltrate can pass. The likelihood of leakage atthis point is further reduced in operation by the Av'pressure on theliquid mixture in tank Iacting to seal the joints between leaves "I4 andheader plate 9.

Forroutine cleanouts itwill be seen that sup ply of compressed air at 32willV put back pressure on 'the filter bags, dislodging the filter cakes-which Will fall t`o the trough bottom for removal cur to personsskilled in the art to which it appertains, within the scope of theappended claim.

It is claimed and desired to secure by Letters Patent: I

1n a filtering device, a housing having spaced side walls, end walls anda top and bottom and an opening in one of said side walls, a cleanoutdoor in the other side wall and a solid material receiving space belowthe level of said opening and said cleanout door; means for supplying aliquid mixf ture to said housing, a header plate detachably Y secured insealing relation to said housing peripherally of said opening, andhaving in the area surrounded by the sealed joint, a plurality ofapertures extending therethrough; a discharge box encasing the externalside of said header plate relatively to said housing and having itsinterior in communication with said apertures, a plurality of hollowleaf type lter units individually and detachably secured to said headerplate in spacedV parallel relation to a vertical plane of reference andhaving their interior spaces in communication with the interior of saidbox through said apertures at substantially theV lowest points of theirsaid interior spaces, said filter units being so formed as to beremovable from vsaid housing as a unit with said header plate.

GUY V. WOOD CHARLES W.BIILBE.

REFERENCES CITED The following references are of record in the le ofthis patent:

(first addition to 343,585)

